Safety switch



Dec. 6, 1927. 1,651,935

C. F: SCHWENNKER SAFETY SWITCH 1 Filed March so. 1922 2 Sheet s-Sheet 1 llll|||| 0 MMMM W Inventor: 4 charlesFfschwennker;

His Attovneg.

Dec. 6, 192?.

c. E'SCHWENNKER S FETY SWITCH Filed March 30, 1922 2 Sheets-Sheet 2 i llw 7mm ai\iiiiivi aESiSE i 553 5.55:

Invent. 0T 1 CharlesFZSchwennKer; by

His Attorney Patented Dec; 6, 1927..

ire sr E- cnnnnns F. sonwnnnnnn, or scnEnncrAnY, new YORK, Assrenon T GENERAL ELECTRIC-COMPANY, A CORPORATION on NEW YORK.

SAFETY swrrcn.

Application filed March 30, 1922. Serial No. 548,121.

The present invention relates to electric switches, and more especially to safety or enclosed switches for power purposes.

Where "electric power is employed for 5, driving industrial apparatus, such as machine tools, it is necessary for the operative to be able to freely controlthe supply of power current thereto, 'an'd on account of the dangerous character of such power currents it has become customary to enclose the fuses, switches and their connections in iron boxes with only the insulated operating handle access'ible to the operative. These enclosures orboxes'a're provided with seals and locks so that they may not be opened except by ;a duly authorized partypand as they must 7 be opened'w-henever a fuse is to be renewed it is desirable that they be made to afford protection to the authorized party while making such renewals by arranging the box lid so that the fuses 'andftheir holders only are exposed when the lid is open, and the switch is so interconnccted with the lid that the electric current is cut off from those parts whenever the lid is moved out of its closed position. v

The object of my invention is to provide an improved safety switch which shall be hardy, highly efficient and compact, which will permit .one portion of its cover to be raised for saferenewal of fuses while the other portion remains fixed over the switch mechanism or permit both portions to be raised as a unit without being detachable from eachother or from the 'box, to permit 7 of repair or renewal of the switch mechanism, and which when closed will be rain shedding.

One embodiment of my invention is shown in the accompanying drawings, in which Fig.

l is a perspective view of the safety switch with the lid in raised. position; Fig. 2 is a similar view with the whole cover in raised position; Fig. 3 is a front elevation with part of cover broken away to show the switch construction: Fig. v taken on line H of Fig. 3 with the switch in closed position; Fig. 5 is a similar fragmentary section with the switch in open po Fig. 6 is a right side elevation of sition; v I

handle and associated parts shown the switch locked by 4 is a vertical section in. closed position; Fig. 7 is an exploded per spective view of the switch handle and associated parts; and Figs. 8 and 9 are fragmentary sections showing detail of pivotal su-pport for the cover.

The casing or box is made up of heavy sheet steel punchings comprising a main portion 1 forming the back and two sides, an upper cover comprises a normally fixed or upper member 6 and a transversely hinged lower member or lid 7. Both members have flanges 8 on three sides adapted to overlap thesides and ends of the box, while adjacent the meet- 1ng edges of the members the flanges 8 are .pivotally'connected by rivets 9 and in such manner that the edge of the hinged member 7 underlies the adjacent edge of the upper member 6, so that when the former member is closed the joint between them will shed water. The upper end portion 2 has a gutter 2, Fig. 6, serving to divert the water from entering the box.

The upper member 6 is mounted on the box by means of a pivotal bracket 10 having angular. end portions 11 terminating in hooked tips 12. These end portions are riveted 'to the inside of the upper member 6 and their hooked tips 12 extend freely through slots 13 in the left side of the box body and are assembled by a forward longitudinal movement therein to hook over the lower end walls of said slots 13 and there arranging the latter relative to the end of the box body that the flange 3 of the upper ,box end 2 upon being connected to the main box portion engages the adjacenttip -12and holds it and its companion in depressed position. By means of this pivotal bracket "the entire cover may be swung out to full o en position without interference between tlie box side and the adjacent on 'tion of the flange 8, and there arrested? by the angular central part of the bracket en gaging with the box sideas is indicated in Fig. 2. The meansfor fastening the upper cover member in closed position consistsof a haspl4 hinged to theisideopposite the pivotal bracket by a lug515 riveted to the inside of the right-hand flange 8Vthereof and provided with a shoulder 16 adapted toe'n-.

gage the inner surface of the hasp" and prevent its swingingxinwardly. sufiiciently to enterthe box when the cover is being closed." The free end of the'hasp is provided with.

the customary slot 17s for the reception of thelug orzstaple 18 fixed on the'sideiof the boxand'adapted to receive a-padlock; The lower edge19 of the hasp'is made cam-shape for a purpose to be set forth later.- The means for fastening in closed position the lowercover member or lid '7 consists-of a pierced lug 20 extending outward from the:

edge; of the lower end 4 of the, box and adapted to pass through a slot 21 formed in thejfree edge otthe lid and to receive a seal orother securing means." Near the hinged side of the lid is riveted an extension or heelplate 22 having a shoulder 23 arranged to engage the side of stop 24 (see Fig. 3) pivoted to a bracket 25 on the inner side of the box and adapted to be swung out by hand when it is desired to temporarilyretain the lid in raised position.

l/Vithinthe box is detachably mounted by means of screws126 a'combined switch and 1 fuse cutout comprising an insulatingbase 27 having mountedethereon 'beneath the lid 7 pairs of alignedlfuse clips 28 and beneath the upper portion 6 of the cover corresponding switch pivot 'cli'ps 29 and contact clips 30, in cooperation with which are switch blades 31 rigidly'connected at their free ends by an insulating bar 32. To this bar are rigidly secured by bolts 33two stiff spring yokes 34, the innerends 35 of which are bent backward and adapted to strike against the insulating base 27 and cushion the hammer blow incident to closing of the switch, while, the opposite ends 36 are bent backward and. upwardly into elbows for free engagement with the switch aotuating rod 37 and serve to cushion'the outward thrust of the switch upon opening. In case it should "become necessary to replace the combined switch andcutout, it is necessary, only to remove the screws 26 and draw it upwardly from beneath the" actuating rod 87-' The actuating rod 37 is bows-shaped and pivoted at one end in the left side'of the box somewhat in front of the axis of the pivots of the switch blades 31 and at the other end in anaxial bore 38 in the crank shaft 39 where it may be fastened bya cotter pin through the latter.

tion' and hugs the elbows when the'switch is in the normal open position as is indicated The bowedpart of the actuating rod 37 rests freely in the elbows" 36-when the switch is in normal closed posi-- in Figs. 4and 5 on accountofthe relative eccentricity of the-Hactuatingrod and the pivotal axis of the switch blades and thereby operates to yieldingly arrest the outward movement of the latter. I

The means for operating the switch-vactu atingrod comprises ai'icrank .40frigid1y inounted'on theouter-end of the shaft 39'. gjournalled in the right-hand side ofthe box andiii which the rod is adaptedto rock independently thereof to provide for av certain lost motion between them, The inner end of the shaft 39 rhas a portion of its cylindrical wall cut away. to provide a \l shaped-notch 4l ,'between the sides of which the bent; port-ion of the rod extends outwardlyiandJwith which it alternately engages when the crank '40 ismoved froin one- :position to the other. 2

p The means for causing the switchto move with a snap action comprisesa spring 42 'a thrust bar 43 threaded surrounding through an. angular end of the bracket25 and pivoted 'to a lug 45 on the-inner end of a U-shaped wrist plate 44 madeof sheet metal and journalled upontheinner end of the crank shaft 39 with its outer end bearing againsttheinner adjacentwall of the box side while the opposite end 45 is formed about the rod .37 to positively lock them an-gularly together, so that when the rod 37 has been rocked by means'of its connection vwith the crank 40, sufiiciently to carry the" 'pivotal point between lug 44 and the thrust rod143 past its dead center the spring 42 is free to react and throw theswitch-actuatw ing rod 37 and withit 'the1switch blades' totheir extreme position, v

The interlocking means whereby the switch is required to be opened before opening of the box lid andalso prevented from'closing while the lid is. out of its closed position i comprises arc-shaped 'keepers "46 'and'47 struck up from a sheet metal'plate 48 rigs idly connected to the inner side of the crank 40 ,andadapted to contact with the heel plate 22 of the. lid. A stop plate 49 'isriveted to the side of the box and hasa bearing ape}? ture 50 aligning with'thebearing aperture in the box for the reception of the crank shatt39, arcuate stop flanges' 51 and 52 at its upper and lower edges and its'right-hand end bent outwardly to f rm the staple 18. The arcuate keeper 46 and the stop flange-5'1 are provided with abrupt ends and so disposed with-relation to each other that theyoperate tjo' arres'tthe crank 40' at the end" of its travel in either directionIjWhenthe t and the latter travels beneath it throughout position the path its movement so that the lid is held down thereby whenever the crank is out of its full off posit-ion.

In order to prevent the hasp 14 being raised while the crank 40 is out of its full off position, the plate 48 is provided with a radial finger 54 which overlies the adjacent cam-shaped edge 19 of the hasp 14 during,

such positions of the crank- In order that the cover may be held in fixed relation to the box mouth while closed and thereby to insure the alignment of the hasp 14 with the parts cooperating therewith, I provide a notch crank 40 down to the position indicated in Fig. 1, the seal or other fastening means removed from the lug'20 and the lid 7 raised and there secured by swinging the stop 24 outwardly behind the shoulder 23 on the heel plate 22. The switch is automatically locked in off position by the tip 53 of the heel plate standing in the path of the upper end of the keeper flange 46. The party renewing the fuses may then insert his hand within the box without danger of shock since all accessible parts are dead, the only live'parts be ing the upper switch clips to which the line wires connect, and they are too remote to be reached.

In case it becomes necessary to inspect, repair or replace the switch, the padlock securing the hasp 14 to its staple 18 must be removed by an electrician or other duly authorized party having the key thereto. The crank 40 must be pulled down to the full off to remove its radial finger 54 from of outward swing of the hasp 14, as indicated in Fig. 1, then upon raising the hasp the entire cover is free to swing back and be there supported normal to the box by the pivotal bracket 10 as indicatedin Fig. 2. In this position of the cover all parts within the box are freely accessible and the switch may be opened and closed without interference of the interlocking means between lid 7 and crank 40.

The Patents 1,524,801, February v3, 1925 and 1,527,709, February 24, 1925 are di-' visions hereof.

While I have shown and described the best embodiment of the invention known to in the edge of the right-hand side of the box in position 1. In an electric switch, the combination of a metal box having slots formed in one side parallel to the front edge thereof, a flanged cover for saidbox, a pivotal bracket on said cover having tions extending outwardly and adapted to enter said slots from the inside of the box and be interlocked with the wall at the ends thereof by a forward longitudinal movement therein, and means to prevent a return longitudinal movement of said tip portions in said slots.

2. In an electric switch, the combination of a metal box comprising a main portion having longitudinal slots formed in one side parallel to the front edge thereof and an end portion provided with a flange adapted to overlap the side and a part of one of the said slots, a flanged cover for said box, a pivotal bracket on the inside of said cover provided with hook-shaped end portions adapted to freely enter said slots from the inside of the box and interlock with the wall at the ends thereof by a forward longitudiby a forward longitudinal movement there-- in, and of said detachable means for engaging one end portions to hold it in advanced position.

4; In an electric switch, the combination of a metal box having slots formed in the rear side parallel to and spaced from the front edge thereof, a cover having a peripheral flange adapted to overlap the sides of said box, a pivotal bracket on the inside of said cover, independent of said flange and having angular end portions adapted to enter thesaid slots from the inside of the box and interlock therewith, and the said bracket having an intermediate portion adapted to abut against the inner wall of the said rear side when said cover is in open position.

In witness whereof, I have hereunto set my hand this 29th day of March, 1922.

CHARLES F. SCHWENNKER. 

